Method of extracting glue and gelatin



Patented Aug. 17 1943 Donald P. Grettie, Chicago, 111., assignor to Industrial Patents Corporation, Chicago, 111., a v

corporation of Delaware No Drawing. Application June 16,

Serial No. 279,552

18 Claims.

This invention relates to amethod of extracting gelatinous material from pork skins, hide trimmings, fleshings, sinews, and the like.

One of the objects of this invention is to provide a method of extracting gelatinous material from gelatinous material stock to yield a high test gelatinous material.

Another object of this invention is to provide a method of extracting gelatinous material from gelatinous material stock without the usual cooking step.v

Further objects and advantages of my inventionwill become apparent from the description and claims which follow.

The present invention contemplates the treatment of gelatinous material stock, such-as pork skins, hide trimmings, fleshings, sinews, and the like, with a gelatinous material peptizing or liquefying agent for a period sufiicient toextract the gelatinous material from the gelatinous material stock followed by a separation of the gelatinous material from. the peptizing or liquefying agent.

The term gelatinous material is used herein.

and it is to be understood to designate all grades of animal gelatin and glue including those intermediate products commonlyknown as low grade gelatiniand high grade glue. The term gelatinous material stock is used herein and it is to be understood to designate animal'waste matter such as snouts, lips, ears, hide trimmings, fleshings, sinews, and the like, a specific example being pork skins.

In 'the'conventional practice'of extracting'gelatinous material from gelatinous mat'erialstock of the type 'described ior example, hide trimmings, thefresh trimmings are preserved by salting'with sodium chloride. The'salted trimmings are stored or shipped to the glue factory and may there be storeduntil required for use; The salted stock must be washed thoroughly to free the stockirom the's'alt before transferring the stock to the lime pits for curing. The curing period 7 requires from four to twelve weeks, depending upon the type of stock,'the temperature, and the amount' of caustic which-is generally'employed to fortify the'lime. The cured stock isthen thoroughly washed and acidified to the correct pI-I, after which it is transferred to cooking vessels and the gelatinous material extracted with water.

In practicing my invention, the gelatinous material stock' is placed in a solution of the peptizing or liquefying agent, If the stock has been preserved by salting with sodium chloride,'it is first washed with water to'remove the salt, after which the stock'is coveredwith a solution of the peptizing or liquefying agent. On soaking of the gelatinous material stock in the solution of the peptizing' or liquefying agent, the stock first swells, and as the gelatinous material is extracted from-the stock the stock'shrinks. The proportion of gelatinous'material extracted is proportional to the concentration of the solution,-the temperatures, and the time of. the soaking. I The liquor containing water, peptizing agent, and gelatinous materialis then separated from the gelatinous material stock residue. The gelatinous material may be separated from the peptizing agent or solution of the peptizing agent as by dialysis or precipitation.

Peptizing or liquefying agents which are satisfactory-.for the purposes of my invention in-. clude a wide variety of substances. They may be classified as water soluble salts of divalent metals, certain phenolic compounds, soluble isothiocyanates, soluble salts of aryl sulphonic acids,

and compounds having a --CQNH2 or -CSNH2 group. Examples of {satisfactory water soluble salts of divalent metal are calcium, zinc, and magnesium chlorides, or nitrates, or calcium lac-. tate. Examples of satisfactory phenolic com pounds are phenol, salicylic acid, or the sodium salt of salicylic acid. Examples of satisfactory soluble isothiocyanates are ammonium, sodium,

and potassium isothiocyanates. Examples of satisfactory soluble salts of arylsulphonic acids are 7 benzene and naphthalene sulphonates. Examples of satisfactory compounds having the groups CONH2 or -'-CSNH2 are urea, thiourea, acetamide, and formamide.

The peptizing or liquefying' agents are to be distinguished'from hydrolyzing agents, such as the strongmineral acids and alkalies, The peptizing agents may be defined as substances which are capahle'ofconverting a jelly into a colloidal solution or sol. without chemical degradationor change-of the material forming the jelly.- Peptizing or 'liquefying agents the jelly is not changed chemically and it is not hydrolyzed, and, as a' result, the gelatinous material obtainedby soluble salts of divalent metals and 'compoundsI having the group -CONH2 or CSNH2 will ex tract about 50 per cent of the available gelatinous,

material from pork skins in about I two days. I

Pork skins contain about 25 per cent to 30 per cent I available gelatin, about 12 per cent gelatinous material, based on the weight of the skin's;- being extracted in two days. Practically all oft'h'e available gelatinous material will be extracted. in. thirty days. If a higher test gelatinous material isdesired, the gel at'inou material stock maiy be subjected to'extraction 36 350" 0"per-cent?solifi ti'ons' for two to th-ree days-and err-transferred tofresh'solutions' Solutionscont n-ing less-'t'han about 1'5 per-cent ofthe liquef'ying agent are satisfactory; but require greater extraction periods and are; therefore; 1ess'-d'esiiable--com= mercia-lly; v v

The flnalllqlior containingthe pepnirr agent, water, and the gelatinous niaterial is separated from the gelatinous rh at'e'ria-l steep residueale-by iil'tr anet-by drai neg'theliriuorfronrtlie stbck residuej The separated-"I i r maybe placed in aporouscontainer, suc'l-i'a G 'bliandb-al? which is then immersed-"in w known; mepeiitinhga enra fer'fiexampiat goal cium sa' lts,'- being a crystalloicl will passtnrecgh porous m mbrane into water; leavin the liquor-conta ning- Waterman gelatinous mate: rial iii-then mus c-8;; Thelimidrmav t he evaporated and driedin any: 'desii ed' niarifier to prepar'ea dried gelatinousmateria i The gelatinous material may te precipitated horntneliquercontainingwater: pestiz'ingiagent; gelatinous material b 'the'additionitofhe li'citi'or ol -a'lcoh'ol. acetoneior saturated solution of: ammonium sul hate; and gelatinou's m ajfterial s'parated fromthesoIutiDhL- In a speoifl'c. example; porkz skins were placed in alsolutioni containing: from 30 per cent to: 50 per cent urea andxh'eld at room temperature: for about" two clays; At therend of the? two? day period; abbut'Sfl per cent olitl'le' available 'geI-at'i nou material-had been extracted-i ron-rthe pork skins. Practically all of the'gelatinoussmate'rial wast extracted: by holding the: pork skins in? the urea? solution for a? period ctr-about: thirty- The liquor containrig watenui'eea andrgeiatinous mat'erial'was' separatedfrofncthe' gelatinous mate". rial: stock residue: The gelatinous-material was separated from the' urea solution, by dialysis or by precipitation: Although the gel'zttinousQma terialextracted in this mannerdidinot have an exceedingly'high' test; it did-have a very: high L: 'As weir phate. Gelatinous material was also separated from another ponion of the liquor by placing the liquor in a Cellophane bag and suspending the Cellophane bag in water to permit the calcium nitrate to be separated from the gelatinous material by dialysis. By removingfithe pork skins from the liquor and placing them in successive fresh solutions of calcium nitrate a higher test gelatinous material was obtained. The gelatin extracted from pork skins by means of a calcium ni'tiatesclution' had a high test and good clarity.

Although any of the peptizing agents mentioned above may be employed, I prefer to employ"urea; form'amide; and the water soluble salts of 'divalnt' metals', for example, the Water soluble salts of calcium. 7

rel-aim? 1-. The method of extracting gelatinous materialirom gelatinousmaterial stock which comprises soaking the stock in an aqueous solution of apeptizing'"ageht at normal temperatures and' for a sufllcient period or timeto extract the gelatinous material front tlie sto'c'l i and tlie'reafter sepia-rat in g-tlie sonata-containing the'ex'ti'aoted gelatinous material from the-gelatinous material stock residue. I

2. The method of extracting gelatiiious mate rial frenigelannsus material stock wl i-icl-r' p n-see seating} the stock' iri -anaqueous somnee o'f a' sal t of a divalent meter at normal-' tempera tures and for a sufficient period of time toextr aot the-gelatinous material from the stock and therearter separating the solution co'ntalhir1gthe ex tracted gelatinous material fio'n'r the gelatinous material stock residuei 35 Thermethodi of extracting gelatinous material from: gelatinous: materialsistechwhich comprises? soaking tlierstnck imam-aqueous solution' 'of azca'lciurn salt? normaltemperaturesi'andlfor a suflicient: periodr or time? tozext'ract theg'e'latinous material fromntlie'stock andithereafter separating theisoluti'on": containing:thezextractedi gelatinous material from the gelatinous material stock iresi' 4; Th' methodvof extracting; gelatinous? mate rial from gelatihousurfaterial stock: whichrcom' prises soaking; the r gelatinous rziaterialls'took z in an. aqueous solutionofzinc chloride? at: normal temperature 5 and for a: sufficient period: of. time to extract-the gelatinous material;

5'. The method of extracting; gelatihousxmatee ri'a-l from. gelatinous materlal stock whichicom prises soaking the stock in an aqueous solution of calcium nitrate at normal temperatures and for a: suthcien-t period 1 of time to" eXtract': the gelatinousfmaterialfrom theistockandztherea'fter separating-1 the solution-containing; the extracted g'e latinou-szmaterial-from the gelatinous material 'i fffisiduea a 7' 6; The methodot extractinggelatinous mateirial from gelatinous-material stock which comprises seakingthe gelatinousmaterial stockin anauueous solution of magnesium: chlorid at normal; tentperature and for asufiicient period of timeeto extractthe gelati nous.material; U I

7.; The method of extracting gelatinous material: mm gelati-nous-tmaterial stockwhich com-'- prises: soakingJthe gelatinous -material stock in an-v aqueoussolutiom ofafi'magnes'iumsa-lt: zit-nor.- malYtempera'ture andfor a sufficient. period of timeto-extraot the gelatinous materlali 8; ThemethodI'of. extracting; gelatinous. material'% from gelatinous material: stock which-1 com pirises soaking the? gelatinousr. masher stock in q ous-s'olution ore: zinc-"salt at normalperature and for a suflicient period of time to extract the gelatinous material.

9. The method of preparing gelatinous material from gelatinous material stock which comprises extracting the gelatinous material from the gelatinous material stock by soaking the stock in an aqueous solution of a peptizing agent at normal temperatures and for a sufiicient period of time to extract the gelatinous material, separating the liquor containing water, peptizing agent and gelatinous material from the gelatinous material stock residue, and separating the gelatinous material from the peptizingagent.

10. The method of preparing gelatinous material from gelatinous material stock which comprises extracting the gelatinous material from the gelatinous material stock by soaking the stock in an aqueous solution of a peptizing agent at normal'temperatures and for a suflicient period of time to extract the gelatinous material, separating the liquor containing water, peptizing agent, and gelatinous material from the gelatinous material stock residue, and separating the gelatinous material from the peptizing agent by dialysis.

11. The method of preparin gelatinous material from gelatinous material stock which comprises extracting th gelatinous materialfrom the gelatinous material stock by soaking the stock in an aqueous solution of a peptizing agent at normal temperatures and for a sufiicient period of time to extract the gelatinous material, separating the liquor containing water, peptizing agent and gelatinous material from the gelatinous material stock residue, and precipitating the rial from gelatinous material stock which comprises extracting the gelatinous material from the gelatinous material stock by soaking the stock in an aqueous solution of a calcium salt at normal temperatures and for a sufiicient period of time 1 to extract the gelatinous material, separating the liquor containing water, salt, and gelatinous material from the gelatinous material stock residue, and separating the gelatinous material from the salt.

14. The method of extracting gelatinous material from gelatinous material stock, which comprises soaking the stock in an aqueous solution containing at least 15 per cent of a peptizing agent at normal temperatures and for a suflicient period of time to extract the gelatinous material from the stock and thereafter separating the solution containing the extracted gelatinous material from the gelatinous material stock residue.

15. The method of extracting gelatinous material from gelatinous material stock which comprises soaking the stock in an aqueous solution containing at least 15 per cent of a water soluble salt of a divalent metal at normal temperatures and for a sufficient period of time to extract the gelatinous material from the stock and thereafter separating the solution containing the extracted gelatinous material from the gelatinous material stock residue.

16. The method of extracting gelatinous material from gelatinous material stock which comprises soaking the stock in an aqueous solution containing at least 15 per cent of a calcium salt at normal temperatures and for a sufficient period of time to extract the gelatinous material from the stock and thereafter separating the solution containing the extracted gelatinous material from the gelatinous material stock residue.

- 17. The method of extracting gelatinous material from gelatinous material stock which comprises soaking the stock in an aqueous solution containing at least 15 per cent of calcium nitrate at normal temperatures and for a sufficient period of time to extract the gelatinous material from the stock and thereafter separating the solution containing the extracted gelatinous material from the gelatinous material stock residue.

18. The method of preparing gelatinous material from gelatinous material stock which comprises extracting the gelatinous material from the gelatinous material stock by soaking the stock in an aqueous solution containing at least 15 per cent of a peptizing agent at normal temperatures and for a sufficient period of time to extract the gelatinous material from the stock, separating the liquor containing water, peptizing agent and gelatinous material from the gelatinous material stock residue and separating the gelatinous material from the peptizing agent.

DONALD P. GRETTIE. 

